JP2023066753A - Deep UV Generating Device, Sterilizer, Deep UV Generating Method, and Sterilizing Method - Google Patents

Abstract

To provide a deep UV generating device capable of efficiently emitting deep UV rays by using Ar, which is an inexpensive rare gas, a deep UV generating method, and a sterilizer, and a sterilizing method.SOLUTION: A deep UV generating device 1 includes a discharge medium 20, a container 10 containing the discharge medium 20, a pair of electrodes 30 and 31 provided in the container 10, and a power supply 40 that applies a pulse voltage or an alternating voltage between the pair of electrodes 30 and 31, and the discharge medium 20 contains argon and water vapor, oxygen or hydrogen, and generates a discharge plasma 60 in the container 10 to emit deep UV rays 70 by applying a pulse voltage or an alternating voltage between the pair of electrodes 30 and 31.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a deep ultraviolet generator, a sterilizer, a deep ultraviolet generating method, and a sterilizing method.

Conventional deep ultraviolet generators include sterilizing mercury lamps and excimer lamps using rare gas and halogen (Patent Documents 1 to 3, etc.). Excimer lamps have different wavelengths depending on the medium. For example, the KrCl excimer has a central emission wavelength of 222 nm.
The deep ultraviolet (DUV) wavelength range of 200 to 300 nm includes UV-C (200 to 280 nm), which is effective for sterilization and sterilization.

JP-A-2000-188085 JP 2008-146906 A JP 2020-080297 A

However, in the conventional deep ultraviolet generator, the mercury lamp emits a spectrum including an ultraviolet wavelength of 254 nm, so it is effective for sterilization, but since mercury is used, it imposes an environmental load upon disposal. An excimer lamp basically uses an expensive rare gas (Kr or Xe) and halogen as a discharge medium.
On the other hand, when Ar, which is an inexpensive rare gas, is used as the discharge medium, the emission intensity in the deep ultraviolet (DUV) wavelength region is weak.

In light of the above-described circumstances, the present invention provides a deep ultraviolet generator that can efficiently emit deep ultraviolet rays using Ar, which is an inexpensive rare gas, a method for generating deep ultraviolet rays, and a sterilization apparatus and sterilization using these. The purpose is to provide a method.

The present invention includes the following aspects.
[1] A discharge medium, a container containing the discharge medium, a pair of electrodes provided in the container, and a power supply for applying a pulse voltage or an alternating voltage between the pair of electrodes,
the discharge medium comprises argon and water vapor, oxygen or hydrogen;
A deep ultraviolet generator for generating deep ultraviolet rays by generating a discharge plasma in the container by applying a pulse voltage or an alternating voltage between the pair of electrodes.
[2] The deep ultraviolet generator according to [1], wherein the discharge medium flows inside the container.
[3] The deep ultraviolet generator according to [1], wherein the discharge medium is enclosed in the container.
[4] The deep ultraviolet generator according to any one of [1] to [3], wherein the discharge medium is in an atmospheric pressure state.
[5] A sterilization device using the deep ultraviolet generator according to any one of [1] to [4].

[6] A discharge plasma is generated in the vessel by applying a pulse voltage or an alternating voltage between a pair of electrodes in the vessel in the presence of a discharge medium containing argon and water vapor, oxygen or hydrogen. a method for generating deep ultraviolet rays, wherein the deep ultraviolet rays are generated by
[7] The method for generating deep ultraviolet rays according to [6], wherein the discharge medium is introduced into the container, and a pulse voltage or AC voltage is applied between the pair of electrodes while discharging the discharge medium.
[8] The method for generating deep ultraviolet rays according to [6], wherein a pulse voltage or an alternating voltage is applied between the pair of electrodes while the discharge medium is enclosed in the container.
[9] The method for generating deep ultraviolet rays according to any one of [6] to [8], wherein the discharge medium is at atmospheric pressure.
[10] A sterilization method using the deep ultraviolet generation method according to any one of [6] to [9].

ADVANTAGE OF THE INVENTION According to this invention, the deep-ultraviolet-ray generator which can emit deep-ultraviolet rays efficiently using Ar which is an inexpensive noble gas, the deep-ultraviolet-ray generation method, and the sterilization apparatus and the sterilization method using these are provided. can do.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows the deep ultraviolet-ray generator 1 of embodiment which concerns on this invention. It is a spectroscopic measurement result of a radiation spectrum generated from a discharge plasma of Ar+H ₂ O. It is a spectroscopic measurement result of a radiation spectrum generated from an Ar discharge plasma. 4 is a graph showing voltage and current waveforms of pulse discharge of Ar+H ₂ O. FIG. 4 is a graph showing voltage and current waveforms of Ar pulse discharge. Fig. 3 is a graph showing the survival rate of HCT-116 (a human colon cancer-derived cell line) after cell irradiation from Ar+H ₂ O discharge plasma. Fig. 3 is a graph showing the survival rate of HCT-116 (human colorectal cancer-derived cell line) after cell irradiation with UV light (312 nm) and germicidal lamp (254 nm). 1 is a schematic diagram showing a deep ultraviolet generator 2 of Example 1. FIG. 3 is a spectroscopic measurement result of a radiation spectrum generated from discharge plasma of each discharge medium 20. FIG. 3 is a spectroscopic measurement result of a radiation spectrum generated from discharge plasma of each discharge medium 20. FIG.

<<Deep UV generator>>
A deep ultraviolet ray generator, which is an embodiment to which the present invention is applied, will be described in detail below. In addition, in the drawings used in the following explanation, in order to make the features easier to understand, the characteristic portions may be enlarged for convenience, and the dimensional ratios of each component may not necessarily be the same as the actual ones. do not have. The present invention is not limited to the embodiments shown below.

FIG. 1 is a schematic diagram showing a deep ultraviolet generator 1 of an embodiment according to the present invention.
The deep ultraviolet generator 1 of the present embodiment includes a discharge medium 20, a container 10 containing the discharge medium 20, a pair of electrodes 30 and 31 provided in the container 10, and between the pair of electrodes 30 and 31. A power supply 40 for applying a pulse voltage or alternating voltage, the discharge medium 20 containing argon and water vapor, oxygen or hydrogen, and applying the pulse voltage or alternating voltage between the pair of electrodes 30 and 31 , a discharge plasma 60 is generated in the container 10 to generate deep ultraviolet rays 70 .

A pair of electrodes 30 and 31 are provided facing each other in a container 10 made of a quartz tube that can transmit deep ultraviolet rays (DUV). The shape of the pair of electrodes 30 and 31 may be rod-like or needle-like, and the material of the pair of electrodes 30 and 31 is preferably tungsten, which is less susceptible to discharge wear, but stainless steel or other metals may also be used.
The distance between the pair of electrodes is not particularly limited, and may be 100 mm or less, 80 mm or less, 40 mm or less, or 10 mm or less.
The distance between the pair of electrodes may be 2-100 mm, 4-80 mm, or 8-40 mm.

In the deep ultraviolet generator 1 of the present embodiment, the discharge medium 20 contains argon and water vapor, oxygen or hydrogen. A discharge plasma 60 can be generated within 10 to efficiently generate deep ultraviolet rays 70 . Specifically, from the discharge plasma 60, the emission spectrum in the wavelength range of ultraviolet rays with a wavelength of 400 nm or less is shifted to the short wavelength side. The emission spectrum emitted from the deep ultraviolet generator 1 of the present embodiment includes a spectrum in the wavelength region (200 to 300 nm) of deep ultraviolet (DUV). UV-C (200 to 280 nm), which has a short wavelength among ultraviolet rays, is included in the spectrum.

In the deep ultraviolet generator 1 of this embodiment, the discharge medium 20 contains argon (Ar) and water vapor (H ₂ O). As the discharge medium 20 , argon (Ar) is bubbled into water and argon (Ar) containing water vapor (H ₂ O) is introduced from the discharge medium inlet 50 and discharged from the discharge medium outlet 51 . The discharge medium 20 is in an atmospheric pressure state and flows at a constant flow rate (for example, 2 L/min) in the container 10 made of quartz tube.

As the discharge medium 20, _argon (Ar ₎ added with oxygen (O ₂ ) or hydrogen (H ₂ ) can also be used. An added one can also be used. Since argon (Ar), which is an inexpensive rare gas, is used as the discharge medium 20, the manufacturing cost of the deep ultraviolet generator 1 can be reduced.

The deep ultraviolet generator 1 of this embodiment employs a form in which the discharge medium 20 flows inside the container 10 . Therefore, the type of the discharge medium 20 can be arbitrarily selected as described above, and the discharge medium 20 can be brought into the atmospheric pressure state. Here, the "atmospheric pressure state" refers to a state in which the discharge medium 20 is not pressurized or depressurized from the atmospheric pressure, except for making the discharge medium 20 flow. A discharge medium 20 may be enclosed within the container 10 . By enclosing the discharge medium 20, mass production of the deep ultraviolet generator 1 can be realized, and the manufacturing cost can be reduced.

The content of water vapor (H ₂ O), oxygen (O ₂ ), or hydrogen (H ₂ ) in the discharge medium 20 inside the container 10 is not particularly limited. When the content of water vapor (H ₂ O), oxygen (O ₂ ), or hydrogen (H ₂ ) is lower than the content of argon (Ar), the discharge plasma can be stably generated in the container. can. The content of water vapor (H ₂ O), oxygen (O ₂ ) or hydrogen (H ₂ ) is preferably 20 vol% or less, more preferably 15 vol% or less, and 10 vol% or less with respect to 100 vol% of the discharge medium 20. More preferred.
The content of water vapor (H ₂ O) in the discharge medium 20 in the container 10 is preferably 0.2×10 ⁻⁴ to 20×10 −4 Vol % with respect to 100 Vol % of the discharge medium 20, and 0.2×10 −4 to 20×10 ⁻⁴ Vol %. 4×10 ⁻⁴ to 10×10 ⁻⁴ Vol % is more preferred, and 1×10 ⁻⁴ to 4×10 ⁻⁴ Vol % is even more preferred.
The remainder of the discharge medium 20 within the vessel 10 is preferably substantially all argon (Ar).

At least a part of the container 10 may be made of a material that transmits deep ultraviolet rays, and a pair of electrodes may be provided so as to face each other. The container 10 may be provided with a discharge medium inlet 50 and a discharge medium outlet 51 , and may be a container 10 capable of enclosing the discharge medium 20 .

As described above, the deep ultraviolet generator 1 of this embodiment is configured such that the discharge medium 20 contains argon and water vapor, oxygen, or hydrogen. Germicidal lamps that use ordinary ultraviolet rays (254 nm) usually use discharge plasma light emission in which mercury (Hg) is added to argon (Ar). ) is not used, the environmental load at the time of disposal can be reduced.

The deep ultraviolet ray generator 1 of this embodiment uses a high-voltage pulse power source with a fast voltage rise as the power source 40 . By using a high-voltage pulse power supply, power can be saved, and running costs can be suppressed. By adjusting the gap between the pair of electrodes 30 and 31 and the gas pressure of the discharge medium 20, it is possible to reduce the voltage and emit deep ultraviolet (DUV) light with an AC power source.

<Sterilizer>
The sterilization apparatus of the present invention uses the deep ultraviolet generator of the present invention described above.
The sterilization apparatus of the present invention uses the deep ultraviolet generator of the present invention described above, and the discharge medium 20 contains argon, water vapor, oxygen, or hydrogen, so that the deep ultraviolet rays 70 can be efficiently generated. In particular, UV-C (200 to 280 nm), which is effective for sterilization and has a short wavelength among ultraviolet rays, can be efficiently generated, so that an excellent sterilization effect is exhibited. Since argon (Ar), which is an inexpensive rare gas, is used as the discharge medium 20, the manufacturing cost of the sterilizer can be reduced.

<<How to generate deep UV rays>>
A method for generating deep ultraviolet rays, which is one embodiment to which the present invention is applied, applies a pulse voltage or an alternating voltage between a pair of electrodes in a container in the presence of a discharge medium containing argon and water vapor, oxygen, or hydrogen. By applying the voltage, a discharge plasma is generated in the container to generate deep ultraviolet rays.

In the deep ultraviolet generation method of this embodiment, the discharge medium is introduced into the container, and a pulse voltage or AC voltage is applied between the pair of electrodes while discharging the discharge medium.

In the deep ultraviolet generation method of this embodiment, the discharge medium is in the atmospheric pressure state.

The deep ultraviolet generation method of the present embodiment can be carried out using the deep ultraviolet generator 1 shown in FIG. 1 described above. The effect of the deep ultraviolet generation method of the present embodiment is the same as the effect of the configuration described for the deep ultraviolet generation device 1 described above.

A method for generating deep ultraviolet rays, which is another embodiment of the present invention, applies a pulse voltage or an alternating voltage between the pair of electrodes while the discharge medium is enclosed in the container.

<Sterilization method>
The sterilization method of this embodiment can use the deep ultraviolet generator of the present invention described above, and the discharge medium 20 contains argon, water vapor, oxygen, or hydrogen, so that the deep ultraviolet rays 70 are efficiently generated. In particular, UV-C (200 to 280 nm), which is effective for sterilization and has a short wavelength among ultraviolet rays, can be efficiently generated, so that an excellent sterilization effect is achieved. Since argon (Ar), which is an inexpensive rare gas, is used as the discharge medium 20, the manufacturing cost of the sterilizer can be reduced.

The present invention will be described in more detail below with reference to specific examples. However, the present invention is by no means limited to the examples shown below.

[Example 1]
A deep ultraviolet generator 2 of Example 1 shown in FIG. 8 was produced.
In the following description, the same numbers are given to the same configurations as those of the deep ultraviolet generator 1 of the embodiment described above, and duplicate descriptions are omitted.
In the deep ultraviolet generator 2 shown in FIG. 8, the container 10 is a quartz tube that can transmit deep ultraviolet (DUV). A pair of rod-shaped electrodes were opposed to both ends of the quartz tube, and the distance x between the pair of electrodes was set to 70 mm. Both of the pair of electrodes 30 and 31 are made of stainless steel.

As the power supply 40, a self-made high voltage pulse power supply (maximum output: 1 J/pulse) of a magnetic pulse compression (MPC) system having a fast voltage rise was used. An oscilloscope was connected to measure the voltage and current changes over time between the pair of electrodes 30 and 31 . Furthermore, a spectroscopic sensor connected to an MPC controller was installed at a position 40 cm from the container 10 to enable measurement of the discharge emission spectrum.

As the discharge medium 20, argon (Ar) is bubbled into water, and argon (Ar) containing water vapor (H ₂ O) is introduced from the discharge medium inlet 50 at a constant flow rate of 2 L/min, and the discharge medium is discharged. It was discharged from the exit 51. The discharge medium 20 was at atmospheric pressure.

A high voltage pulse voltage was applied between the pair of electrodes 30 and 31 from the power supply 40 . FIG. 2 shows the result of spectroscopic measurement of the radiation spectrum generated from the discharge plasma of Ar+H ₂ O and transmitted through the quartz tube. Ultraviolet rays (UV) are generated on the short wavelength side, and the long wavelength side (680 nm or more) is a typical Ar spectral line. In particular, deep ultraviolet (DUV), including UV-C (200-280 nm), yielded three spectral peaks with a maximum at 218 nm. FIG. 4 shows waveforms of pulse discharge voltage and current when the pulse repetition frequency is 250 Hz. The pulse voltage reached 24 kV and the pulse current reached about 450A.

[Comparative Example 1]
In the same manner as in the deep ultraviolet generator 2 of Example 1 shown in FIG. applied. FIG. 3 shows the result of spectroscopic measurement of the radiation spectrum generated from the Ar discharge plasma and transmitted through the quartz tube. No ultraviolet (UV) generation was observed. FIG. 5 shows waveforms of pulse discharge voltage and current when the pulse repetition frequency is 250 Hz. The pulse voltage reached 24 kV and the pulse current reached about 450 A, and there was little difference from the waveforms in the first embodiment.

[Example 2]
In the same manner as in the deep ultraviolet generator 2 of Example 1 shown in FIG. Voltage was applied (irradiation time: 60 s, pulse repetition frequency: 4, 50, 100, 250 Hz), and HCT-116 (human colon cancer-derived cell line, cell number: RCB2979, obtained from RIKEN BioResource Research Center) was irradiated with deep ultraviolet rays. Cell counts before and after cell irradiation were measured using Cell Counting Kit-8 (Dojindo Laboratories, Inc.) according to the optimal cell number determination method to determine survival rates after cell irradiation.
The results are shown in FIG. The vertical axis in FIG. 6 indicates cell viability, and the horizontal axis in FIG. 6 indicates pulse repetition frequency. Using the deep ultraviolet ray generator of the present invention, a sterilization effect comparable to that of the sterilization lamp of Comparative Example 3, which will be described later, was obtained. Therefore, the deep ultraviolet ray generating device and the deep ultraviolet ray generating method of the present invention are useful as devices and methods for sterilizing many bacteria, and also useful as devices and methods for inactivating many viruses.

[Comparative Examples 2 and 3]
Using a UV irradiation device (LX-312, VILBER LOURMAT, France), HCT-116 (human colorectal cancer-derived cell line) placed at a position of 300 mm directly below the lamp was irradiated with UV light (312 nm) (irradiation time: : 32 s, irradiation intensity: 50, 100 mW/cm ² , Comparative Example 2).
Using a 15W germicidal lamp (GL15, Panasonic), HCT-116 (human colon cancer-derived cell line) placed at a position 300 mm directly below UV light (254 nm) was irradiated (irradiation time: 32 s, irradiation intensity: : 60, 120 mW/cm ² , Comparative Example 3).
By measuring the number of cells before and after cell irradiation in the same manner as in Example 2, the survival rate after cell irradiation was obtained.
The results are shown in FIG. 7, respectively. The vertical axis in FIG. 7 indicates cell viability, and the horizontal axis in FIG. 7 indicates irradiation intensity.

[Example 3]
In the deep ultraviolet generator 2 of Example 1 shown in FIG. , a high voltage pulse voltage was applied between the pair of electrodes 30 and 31 . FIG. 9 shows the result of spectroscopic measurement of the radiation spectrum generated from the discharge plasma of Ar+H ₂ O and transmitted through the quartz tube. Ultraviolet rays (UV) are generated on the short wavelength side, and the long wavelength side (680 nm or more) is a typical Ar spectral line. In particular, deep ultraviolet (DUV), including UV-C (200-280 nm), yielded three spectral peaks with a maximum at 218 nm. When the voltage and current waveforms of the pulse discharge at this time were measured, a pulse waveform with a maximum voltage value of 180V and a current maximum value of 352A was obtained.

[Comparative Example 4]
In the deep ultraviolet generator 2 of Example 3, as the discharge medium 20, oxygen (O ₂ ) was bubbled into water at a constant flow rate of 2 L/min to generate oxygen (O ₂ ) containing water vapor (H ₂ O). , a high voltage pulse voltage was applied between the pair of electrodes 30 and 31 from the power supply 40 in the same manner except that the discharge medium was introduced from the discharge medium inlet 50 and discharged from the discharge medium outlet 51 . FIG. 9 shows the result of spectroscopic measurement of the radiation spectrum generated from the discharge plasma of O ₂ +H ₂ O and transmitted through the quartz tube. Although the generation of ultraviolet (UV) radiation was observed, the overall emission intensity was weak compared to the radiation spectrum generated from the Ar+H ₂ O discharge plasma of Example 3.

[Comparative Example 5]
In the deep ultraviolet generator 2 of Example 3, as the discharge medium 20, helium (He) is bubbled into water, and the helium (He) containing water vapor (H ₂ O) is discharged at a constant flow rate of 2 L/min. A high voltage pulse voltage was applied between the pair of electrodes 30 and 31 from the power source 40 in the same manner except that the discharge medium was introduced from the medium inlet 50 and discharged from the discharge medium outlet 51 . FIG. 9 shows the result of spectroscopic measurement of the radiation spectrum generated from the He+H ₂ O discharge plasma and transmitted through the quartz tube. No ultraviolet (UV) generation was observed.

[Example 4]
In the deep ultraviolet generator 2 of Example 3, as the discharge medium 20, argon (Ar) was mixed with a donor gas of oxygen (O ₂ ) at a volume ratio of Ar:O ₂ =9:1, and the flow rate was constant at 2 L/min. , except that a mixed gas of argon (Ar) and oxygen (O ₂ ) was introduced from the discharge medium inlet 50 and discharged from the discharge medium outlet 51. , 31 was applied. FIG. 10 shows the results of spectroscopic measurement of the radiation spectrum generated from the Ar+O ₂ discharge plasma and transmitted through the quartz tube, together with the results of Example 3. In FIG. Ultraviolet (UV) occurs on the short wavelength side, and in particular, deep ultraviolet (DUV) including UV-C (200-280 nm) gave three spectral peaks.

[Example 5]
In the deep ultraviolet generator 2 of Example 3, as the discharge medium 20, argon (Ar) was mixed with a hydrogen (H ₂ ) donor gas at a volume ratio of Ar:H ₂ =9:1, and the flow rate was constant at 2 L/min. , except that a mixed gas of argon (Ar) and hydrogen (H ₂ ) was introduced from the discharge medium inlet 50 and discharged from the discharge medium outlet 51. , 31 was applied. FIG. 10 shows the results of spectroscopic measurement of the radiation spectrum generated from the Ar+H ₂ discharge plasma and transmitted through the quartz tube, together with the results of Examples 3 and 4. In FIG. Ultraviolet (UV) occurs on the short wavelength side, and in particular, deep ultraviolet (DUV) including UV-C (200-280 nm) gave three spectral peaks.

All of the three donor gases, H ₂ O, H ₂ and O ₂ , had the same spectral shape in the short wavelength region of 400 nm or less, although there was some difference in intensity.
If one of H ₂ O, H ₂ , and O ₂ is added to Ar as a donor gas, a discharge plasma is generated, and deep ultraviolet rays (DUV) including UV-C (200 to 280 nm) are emitted satisfactorily. I was able to

The deep ultraviolet generator and the method for generating deep ultraviolet rays of the present invention can obtain a spectral peak with a good intensity in the wavelength region of deep ultraviolet (DUV). It can be used in a wide range of applications such as an apparatus and deactivation method, an air cleaning apparatus and air cleaning method, a semiconductor cleaning apparatus and cleaning method, a deodorizing apparatus and deodorizing method, and the like.

DESCRIPTION OF SYMBOLS 1... Deep ultraviolet-ray generator, 10... Container, 20... Discharge medium, 30, 31... Pair of electrodes, 40... Power source, 50... Discharge medium inlet, 51... Discharge medium outlet, 60... Discharge plasma, 70... Deep UV light, x: distance between a pair of electrodes

Claims (10)

A discharge medium, a container containing the discharge medium, a pair of electrodes provided in the container, and a power supply for applying a pulse voltage or an alternating voltage between the pair of electrodes,
the discharge medium comprises argon and water vapor, oxygen or hydrogen;
A deep ultraviolet generator for generating deep ultraviolet rays by generating a discharge plasma in the container by applying a pulse voltage or an alternating voltage between the pair of electrodes. 2. The deep ultraviolet generator of claim 1, wherein the discharge medium flows within the container. 2. The deep ultraviolet generator according to claim 1, wherein said discharge medium is enclosed within said container. 4. The deep ultraviolet ray generator according to any one of claims 1 to 3, wherein the discharge medium is at atmospheric pressure. A sterilization device using the deep ultraviolet ray generator according to any one of claims 1 to 4. By applying a pulse voltage or an alternating voltage between a pair of electrodes in the container in the presence of a discharge medium containing argon and water vapor, oxygen or hydrogen, a discharge plasma is generated in the container to emit deep ultraviolet rays. A method for generating deep ultraviolet rays. 7. The method of generating deep ultraviolet rays according to claim 6, wherein the discharge medium is introduced into the container, and a pulse voltage or an AC voltage is applied between the pair of electrodes while discharging the discharge medium. 7. The method for generating deep ultraviolet rays according to claim 6, wherein a pulse voltage or an alternating voltage is applied between the pair of electrodes while the discharge medium is enclosed in the container. The method for generating deep ultraviolet rays according to any one of claims 6 to 8, wherein the discharge medium is at atmospheric pressure. A sterilization method using the deep ultraviolet generation method according to any one of claims 6 to 9.

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